Flow-controller for cellulosic solutions



F. G. KRAFT.

FLOW CONTROLLER FOR CELLULOSIC SOLUTIONS. APPLICATION FILED JAN. 16, 1920.

Patented Sept. 6, 1921.

KNMTEE STATES FREDERICK Gr. KRAFT, 0F "WILMINGTQN, DEL WVARE,

'FATEN NEIMQ'URS & COIVIPANY, 015 WILMINGTON, DELAITAltE, A CUREQRAEIQN Q12 DEE-i FLGFT-GONTEOLLEB 330% GELL'ULQSIC SUL'UTIONS.

To all whom it may concern:

Be it known that I, FREDERICK Gr. KRAFT, a citizen of the United States, and a resident of Wilmington, in the county of New Castle and State of Delaware, have invented a certain new and useful Flow-Controller for Cellulosic Solutions, of which the following is a specification.

This invention relates to flow controllers and has more particular reference to a flow controller for usein controlling the flow of cellulosic solution from the source of supply to the spinneret, in the manufacture of artificial silk.

In the manufacture of artificial silk it is of the highest importance that the thread issuing from the spinneret be of uniform character throughout its length. To this end the character of the solution is as far as possible maintained unchanged; but this alone is not sufficient. It is also necessary that equal volumes of the solution in equal units of time be delivered to, and passed by, the spinneret. The principal difficulty to be overcome is changes in flow due to fluctuations in the pressure of the solution. Various devices whose object is the insuring of uniform flow have heretofore been proposed; but each has certain very real faults, the principal of these being complication of parts rendering the devices ill-fitted for use with viscous solutions, the lagging of the regulating means behind changes in the fluid pressure, and inadaptibility to continuous operation.

I have devised a flow controller which will always deliver to the spinneret equal volumes of fluid in equal units of time, regardless of variations in the pressure of the fluid, which has a minimum of working parts and so is well adapted for use with viscous solutions, and which can be operated continuously, use of the device entailing no discontinuance of the desired continuous and uninterrupted flow to the spinneret.

One object of my invention is to provide a flow controller which shall deliver equal volumes of fluid in equal units of time regardless of the pressure of the fluid, shall be without complicated mechanism, and whose use will entail no discontinuance of the flow to the spinneret.

To this end, and also to improve generally upon devices of the character indicated, my

Specification of Letters Patent.

Patented Septo (5, 119 211.

Application filed January 16, 1920. Serial No. 351,979.

Fig. 3 is an end View of the rotor, showing in dotted lines the location of its bores, but with the pistons omitted to avoid confusion also, the locations of the ports are conventionally indicated;

Fig. 4: is a side view of the rotor with the,

pistons omitted, the rotors driving shaft being shown;

Fig. 5 is a cross-sectional view of the rotor taken substantially on the line 5-5 of Fig. 4, but showing a piston in place in its associated bore, and

Fig. 6 is a side View of a rotor provided with fluid spaces of a type somewhat different from those illustrated in Figs-1, 3, a and 5, the pistons being omitted to avoid confusion and the ends of the rotor omitted to economize space; also the location of the ports is conventionally indicated.

Figs. 4 and 6, and Figs. 3 and 5, are to somewhat larger scales than are Figs. 1 and 2.

Referring now to the drawings, and more particularly to Figs. 1 to 5 :The illustrated controller comprises a casing 1 with suitable inlet and outlet ports 2 and 3, and a cylindrical rotor, or fluid-Space-providing-element, 4: mounted concentrically and fluidtight in the cylindrical bore 5 of the casing 1 to rotate upon its longitudinal axis in the bearing presented by the bore, the rotor being driven by mechanical power through the shaft 6. A suitable number, as three, of-

till

pistons are caused solely by difference in fluid pressure between the inlet and the outlet side. The fluid has no tendency to turn the rotor, the rotations per unit of time depending solely upon the speed of the driving shaft.

The device is intended for placing in the fluid upply line between the source and a spinneret, the rotor being driven at a speed to deliver the desired amount of fluid to the spinneret. In operation (see 5) the in coming fluid, entering the chamber C acts on the piston 8 and pushes,it to the other end of its stroke, the chamber C filling with fluid. Upon the stroke of the piston, the piston expels an amount of fluid equal to the piston displacement from the chamber C this chamber having been filled with fluid earlier in the rotation in a manner like that just described in referring to the chamber C The fluid displaced from the chamber C by the piston passes on to the spinneret tirough a suitable discharge pipe (not shown) it being understood, of course, that the fluid in such pipe is under pressure and the pipe filled, whereby for practical purposes only the amount of fluid displaced by the piston will leave the fluid space C It will be seen that a device embodying the described features accurately controls and determines the fiow to the spinneret, regardless of the amount of, or fluctuations in, the pressure of the fluid; for no matter what the pressure the fluid cannot pass the controller unless the rotor be turning and the pressure in no way affects the speed of rotation, for that, is determined solely by the speed of the mechanically driven shaft 6. Since the device has no controlling parts depending for their functioning on fluctuations in the pressure there is no question of the accuracy of the flow being destroyed by lag of such parts behind the pressure changes. Since the device contains no cams, levers, springs or the like to be exposed to the dragging and damping eflect of the fluid it is advantageously usable to control heavy, viscous and thick fluids. Also, the device can be continuously operated, it not being necessary to discontinue the flow at intervals to place the device in condition for fur their operation. Moreover its small number of parts permits it to be built in extremely small sizes, whereby, without undue comphcation of apparatus, one controller can, if desired, be installed for each spinneret of a large number.

The detailed construction of the illustrated apparatus (Figs. 1 to 5) is as follows:The bore 5 of the casing l is reduced to provide a bearing surface 5 and a shoulder'o and is close at one end by the screw plug 9. The rotor 4. is received between the plug 9 and the shoulder 5 being fitted substantially fluid-tight in the easing and prevented from longitudinal move ment by adjustment of the plug 9. The surface 5 provides a bearing for the shaft 6, the shaft being additionally borne by the stufling-boX-screw 10 whose bearing surface 10 registers with the surface o The con nection between the shaft and rotor is a simple tongue-and-slot connection 1112. The shaft may be driven in any desirable way, as by connecting the pulley 13 with driving mechanism (not shown) of the silkmaking apparatus.

The casing 1 is provided at each side with a slot 2 0r 3, forming the before-mentioned ports and each of a length such that all three bores 7 can register therewith. To provide for suitable connections to piping (not shown) the casing carries plates 14, one at each side thereof, each provided with a threaded aperture 15 or 16 for connection with an inlet or outlet pipe, the aperture 155 being in communication'with the various chambers C C by way of the adjacent slot 2, and the aperture 16 being in communication with the chambers by way of the slot 3. A suitable base 17 may be provided for the casing if desired.

Each piston (Fig. 5) is made up of a pin 18 having a head 19, and a screw 20 having a head 21 and screwed into the pin 18. The pin 18 has a substantially fluid-tight sliding fit in the reduced portion 7 of the bore 7; the heads 19 and 21 preferably fit quite loosely in the chambers, and bottom against the bottom shoulders 7 rovided by the reduction 7 and thus limit the stroke of the piston, the screw 20 furnishing a means for determining the length of the stroke. By fitting the piston heads but loosely in the chamber easy movement of the piston is insured since the formation of a vacuum between the piston heads and chamber bottoms is avoided, with this arrangement the amount of fluid discharged from a chamber depends upon piston displacement and not on chamber capacity.

In order to reduce pulsation it is desirable to so arrange the ports and fiuidspaces that more than one fluid space at a time shall be in communication with a port, the discharges overlapping. To this end and as conventionally indicated in Fig. 3 by the dotand-dash lines the ports 2 and 3 may be of such width that tWo chambers shall always communicate therewith. To this same end, the fluid spaces may overlap circumferentially of the rotor, this construction being shown more particularly in Fig. 6; the location of the ports 2 and 3 is conventionally indicated by dot-and-dash lines. In this figure there is also shown a somewhatmodified form of fluid space, the ends of the through-bores being enlarged to such an extent that each space as U or C extends wholly across the rotor and is a species of groove. As will be understood the pistons for use with this type of fluid space may conveniently be the sam as those already de scribed, their shanks sliding fluid-tight in the bore reductions 7 and their heads alternately bottoming on the surfaces as T @f course sufficient land between the ports 2 and 3 is provided, and the fluid spaces are so located and dimensioned, that no fluid space will be in communication with both ports simultaneously. The stroke of a piston is of course limited to provide that the piston does not project to interfere with rotation, and yet is desirably such as to provide substantially maximum displacement. Although three pistons, equally spaced circumterentially, have been shown, such an arrangement being desirable to eliminate pulsations, it will be understood that any suitable number and spacing can be used. Also, although I describe the rotor as rotably mounted and so forth I do not mean thereby to exclude constructions in which the rotor turns through less than 360 as in an oscillatory movement.

Although I have described my invention with more particular reference to the illustrated embodiment it will be understood that I do not restrict it thereto. indicated devices embodying the invention are more particularly intended for use in controlling solutions used in making artiflcial silk, in their flow to the spinneret, the pistons being operated by the solution because of there being, of course, a greater fluid pressure in the line between the device and the fluid source, than exists in the line between the device and the outlet or spinneret; but if desired devices of the invention may be adopted for other uses.

1 claim:

1. In a flow controller, a casing providing a bearing, an element concentrically received substantially fluid-tight in said bearing for turning movement therein upon its longitudinal axis only, said casing having fluid passages communicating with said bearing and said element presenting fluid spaces for registration with said passages, means associated with said spaces, and operable by the fluid, for permitting one space to fill with fluid and for simultaneously expelling fluid from the other-space, and means for turning said element.

' 2. In a flow controller, a casing providing a bearing, an element concentrically received substantially fluid-tight in said bearing for turning movement therein upon its longitudinal axis only, said casing having fluid passages communicating with said bearing and said element presenting fluid spaces for registration with said passages, means associated with said spaces, and operable by the fluid, for permitting one space to fill with fluid and for expelling fluid from the As previously 1 other space, and means "for turning said element, such means and said first-named means being, as regards the driving of said element, operatively independent and structurally unrelated,whereby fluid pressure upon said first named means cannot turn said element.

8. In a flow controller, a casing providing a bearing, an element concentrically received substantially fluid-tight in said bearing for turning movement the-rein upon its longitudinal axis only, said casing having opposite fluid passages communicating with said bearing and said element presenting a diametrical through-bore located to register at its ends with said passages and having its intermediate portion reduced to provide a bearing at such portion and a fluid space at each end of the bore, a double-headed piston having its shank borne by said intermediate portion and its heads lying in said spaces to bottom on the bottoms of said spaces, the distance between said heads being greater than the bottom-to-bottom distance between said spaces; and means for turning said element, such means and said piston being, as regards the driving of said element, operatively independent and structurally unrelated, whereby fluid pressure upon said piston cannot turn said element.

A. In a flow controller, a casing providing a bearing, an element concentrically received substantially fluid-tight in said bearing for turning movement therein upon its longi tudinal axis only, said element being provided with a through-bore presenting a radially located fluid space at each end and said casing being provided with fluid passages located for registration with said spaces, a piston received substantially fluidtight in said bore to reciprocate therein and having its ends in communication each with the adjacent fluid space, there being provisions for limiting the stroke of said piston, and means for turning said element, such means and said piston being, as regards the driving of said element, operatively independent and structurally unrelated, whereby fluid pressure upon said piston cannot turn said element.

5. In a flow controller, a casing providing a bearing, an element concentrically received substantially fluid-tight in said bearing for turning movement therein upon its longitudinal axis only, said element being pro vided with a through-bore presenting a radially located fluid space at eachend and said casing being provided with fluid passages located for registration with said spaces, a piston received substantially fluidtight in said bore to reciprocate therein and having its ends in communication each with the adjacent fluid space, there being provisions for limiting the stroke 01": said piston and for determining the length of. the stroke, and means for turning said element, such means and said piston being, as regards the driving of said element, operatively independent and structurally unrelated, whereby tluid pressure upon said piston cannot turn said element.

6. in a flow controller, a casing providing a longitudinal bore-like bearing slotted at its sides to present an inlet passage and a diametrically opposite outlet passage, an element concentrically received substantially fluid-tight in said bearing for turning move ment therein upon its longitudinal axis only, said element being provided with a plurality of longitudinally separated diametrical through-bores located to register at their ends with the slots of said casing and each presenting a pair or" fluid spaces one at each end of the bore, and a double-ended piston mounted to reciprocate in each bore with its ends received one in each space, there being provisions for limiting the stroke of the piston, and means for turning the element, such means and said pistons being, as regards the driving of said element, operatively independent and structurally unrelated, whereby fluid pressure upon said pistons cannot turn said element. u

7. In a flow controller, a casing providing a longitudinal bore-like bearing presenting at its sides an inlet passage and a circumferentially spaced outlet passage, an element concentrically received substantially fluidtight in said bearing for turning movement therein upon its longitudinal axis only, said element being provided with a plurality of longitudinally separated and circumferentially spaced through-bores located to register at their ends with the said passages and each presenting a pair of radially located fluid spaces one at each end of the bore, a double-endedpiston mounted to reciprocate in each bore with its ends in communication each With an ad acent fluid space,

said passages and fluid spaces being rel-' atively located to provide that a plurality of said spaces shall simultaneously be in communication with said inlet passage and the related opposite spaces in communication with said outlet passage, there being prd visions for limiting the strokes of said pistons, and means for turning said element, such means and said pistons being, as regards the driving of said element, operatively independent and structurally unrelated, whereby fluid pressure upon said pistons cannot turn said element.

8. In a flow controller, a casing providing a longitudinal bore-like bearing slotted at its sides to present an inlet passage and a diametrically opposite outlet passage, an element concentrically received substantially fluidtight in said bearing for turning movement therein upon its longitudinal axis only, said element being provided with a plurality of lon itudinally separated and circumferentially spaced diametrical throughbores located to register at their ends with the slots of said casing and each presenting a pair of chambers one at each end of the bore, and a double-headed piston mounted to reciprocate in each bore with its head received one in each chamber of the bore, there being provision for determining the stroke of the piston as substantially equal to the effective depth of a chamber, and means for turning the element.

9. In a flow controller, a casing provided with an inlet and an outlet port, an element received in said casing for turning movement therein, said element being provided with a through-bore, reduced intermediate its ends to provide a piston bearing and to present a bottom-shoulder adjacent each end of said bore, and a piston mounted in said bore to reciprocate therein, said piston being composed of a pin having a head and or" a headed element received in said pin, the body of said pin bearing in the reduced portion of said bore and the heads of said pin and element lying in the ends of said bore to bottom upon said bottom-shoulders, the distance between said heads being'greater than the distance between said shoulders.

In testimony whereof I afiix my signature.

FREDERICK G. KRAFT. 

